Caramelized Onion and Parmesan Burgers

Gather the ingredients.

Heat the olive oil in a large heavy skillet over medium heat. Add the onions and sauté for 15 to 20 minutes until they are golden brown and very soft….if you can sauté them for 30 to 40 minutes, even better. Let them cool to room temperature and roughly chop them.

Meanwhile, wipe off any dirt from the mushrooms with a damp paper towel, trim off the bottoms of the stems, then cut the mushrooms in half. Working in two batches, pulse them in a food processor with a metal blade until they are coarsely chopped, much like crumbly ground beef.

Place the mushrooms in a large mixing bowl and add the beef, chopped onions, eggs, panko, Parmesan, and parsley. Gently shape the mixture into 8 patties of equal side, about 3/4 –inch thick. Place them on a cutting board or a platter and refrigerate them for an hour until firm.

Lightly oil a grill pan or a cast iron skillet, or spray with nonstick cooking spray. Heat the pan over medium high heat.

Cook the patties, in batches, until they are cooked through, about 8 minutes on each side – you want to get a nice sear on both sides, but make sure they don't burn, and flip them gently, as they are a bit delicate. Adjust the heat as needed.